What is a door contact ?
The door contact is a means by which the door or window is monitored. It consists of two elements: a contact and the magnet. Installed one next to the other, the door contact on the framedoor and the magnet on the door. Consequently, when the door opens. It moves away the magnet from the contact. As a result, the contact sends a signal to the panel
How a door contact works ?
Any contact has a very simple operation. Indeed it covers in its interior two spaced wires. When the contact is close to the magnet, the magnetic effect causes the two wires to touch each other. In the other hand, when the magnet moves away from the contact due to the opening of the door, the wire separates. Accordingly the panel knows the position of the door. Weather it is open or close
The diagram opposite illustrates the operation of a contact. At the top we see a contact far from its magnet so the two wires do not touch. At the bottom, we see that the two wires are touching because the magnet is near.
The two contact wires are connected to the panel. Thus, it monitors the continuity of the circuit to know the state of the door.
Types of door contact:
Most of the contacts are only an adaptation of the same principle for the different kinds of doors, we find:
Recessed door contact
This type of contact installation is flush-mounted. It is invisible. The cable that connects it to the panel is also invisible.
to install it, we make a hole in the doorframe. And opposite to him on the door we make as well an other hole for its magnet.
This type of contact respects aesthetics since it is not visible. Therefore, in many buildings it might be preferred. For example: big hotels, historic sites where we want to preserve the old aspect … etc this can be a good reason for choosing it by some customers
Surface door contact
is installed on the surface of the door at the corner. Even if the contact is surface. The cable that connects it to the panel is not visible. Either embedded in the wall or in a conduit to avoid sabotage and also for aesthetic reasons. This kind of a contact is not really bulky. And not automatically ugly on a door because It can have multiple colors to match the color of the door
corner of a door
Il n’y a pas de différence entre les deux contact en terme d’efficacité. Mais c’est la visibilité du câble qu’il faut éviter. Car dans le cas d’un contact encastré, le câble est forcement encastré. Par contre le contact surface pourrait être câblé en surface ce qui n’est pas conseillé.
Garage door contact
The alarm system supervises also garage doors. Thus there are contacts especially for that. These are more solid contacts because a garage door could be a loading or unloading door. In a warehouse or a factory garage doors are exposed to knocks. Because of the activity that may take place around.
In sum, this type of contact is stronger. They can be installed either at the top of the door or at the bottom.
Ce type de contact est plus solide car il est fait pour des portes de garages et d’entrepôts. Ils peuvent aussi être installés soit en haut de la porte ou en bas.
Contact enfoncé ( jumper ) : le principe pour ce type de contact est différent. Par ce que le changement de l’état du contact se fait si on appuie sur le contact. Et donc on pas d’aimant. On installe ce contact de façon à ce que la porte enfonce le contact quand elle est fermée. Et le relâche si elle est ouverte.
